poll() 操作经验点滴

1、client端进程挂掉后, server端poll收到的POLLIN不是HUP,ERR

 

2、当poll监视的fd被关闭时, poll并不能及时发现,通常有很大的延迟.不可用来做实时处理.code snatch
    fdarray[0].fd = sock;
    fdarray[0].events = POLLIN;
    fdarray[0].revents = 0;
    fdarray[1].fd = udpsock;
    fdarray[1].events = POLLIN;
    fdarray[1].revents = 0;

    printf("poll ... ...\n");
    ret = poll(fdarray, 2, -1);
    printf("poll ret == %d\n", ret);
    if (ret < 0) {
        perror("poll err");
    }
   
    if (ret > 0) {
        if (fdarray[0].revents&(POLLNVAL|POLLIN)) {
            if (fdarray[0].revents&POLLNVAL)
                printf("sock have except ,,\n");
            else if (fdarray[0].revents&POLLIN)
                printf("sock have pollin ,,\n");
            /* release some resource */
            pthread_exit(NULL);
        }

        if (fdarray[1].revents&POLLIN) {
            printf("udpsock have pollin\n");
            /* read pkt and reply */
        }
    }